Nausea and vomiting (NVP) of some degree occurs in about 75% of all pregnancies but rather little in known of its causes, of factors associated with it, or of its effects both direct and indirect upon the developing fetus. Studies that have appeared suggest NVP is a favorable prognostic sign, in that it is more likely to occur in women who do not abort naturally, who have a longer gestation and a higher birth weight infant. Our own studies have indicated that women who experience NVP are more likely to diminish smoking (as well as ingestion of alcoholic beverages) during pregnancy, suggesting one of possible (partial) mechanism for its effect. Our goal is a prospective study of: 1) maternal factors correlated with occurrence of NVP, including "demographic" factors pre-existing the pregnancy, as well as those varying during pregnancy, including maternal nutrition, weight, smoking, etc., 2) pregnancy outcomes (abortion, infant birth weight, gestation length, sex ratio, birth defects) as associated with NVP after adjustment for effects of associated variables. We wish to determine what factors mediate the apparent protective effects of NVP upon the fetus, and whether pharmacologic suppression of NVP has an adverse effect upon pregnancy, one that is perhaps masked by the apparent more favorable prognosis associated with the complex that is treated.